EP0760578A3 - Image forming apparatus and modulating method therein - Google Patents

Image forming apparatus and modulating method therein Download PDF

Info

Publication number
EP0760578A3
EP0760578A3 EP96202904A EP96202904A EP0760578A3 EP 0760578 A3 EP0760578 A3 EP 0760578A3 EP 96202904 A EP96202904 A EP 96202904A EP 96202904 A EP96202904 A EP 96202904A EP 0760578 A3 EP0760578 A3 EP 0760578A3
Authority
EP
European Patent Office
Prior art keywords
recording signal
period
clock signal
signal
multivalued
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP96202904A
Other languages
German (de)
French (fr)
Other versions
EP0760578B1 (en
EP0760578A2 (en
Inventor
Masaki c/o Canon K.K. Ojima
Masaharu c/o Canon K.K. Ohkubo
Takashi c/o Canon K.K. Kawana
Michio Itoh
Hiroshi Mano
Hiroshi c/o Canon K.K. Sasame
Kaoru Seto
Hiromichi Yamada
Hiroshi c/o Canon K.K. Atobe
Tetsuo Saito
Atsushi Kashihara
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP1255294A external-priority patent/JP3037345B2/en
Priority claimed from JP26822789A external-priority patent/JPH03131125A/en
Priority claimed from JP1299732A external-priority patent/JP2940963B2/en
Application filed by Canon Inc filed Critical Canon Inc
Publication of EP0760578A2 publication Critical patent/EP0760578A2/en
Publication of EP0760578A3 publication Critical patent/EP0760578A3/en
Application granted granted Critical
Publication of EP0760578B1 publication Critical patent/EP0760578B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/40—Picture signal circuits
    • H04N1/40025—Circuits exciting or modulating particular heads for reproducing continuous tone value scales
    • H04N1/40043—Circuits exciting or modulating particular heads for reproducing continuous tone value scales using more than one type of modulation, e.g. pulse width modulation and amplitude modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/40—Picture signal circuits
    • H04N1/40025—Circuits exciting or modulating particular heads for reproducing continuous tone value scales
    • H04N1/40037—Circuits exciting or modulating particular heads for reproducing continuous tone value scales the reproducing element being a laser
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/40—Picture signal circuits
    • H04N1/405—Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
    • H04N1/4055—Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels producing a clustered dots or a size modulated halftone pattern
    • H04N1/4056—Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels producing a clustered dots or a size modulated halftone pattern the pattern varying in one dimension only, e.g. dash length, pulse width modulation [PWM]

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Facsimile Image Signal Circuits (AREA)
  • Laser Beam Printer (AREA)
  • Dot-Matrix Printers And Others (AREA)
  • Color, Gradation (AREA)

Abstract

A multivalued input recording signal is subjected to pulse-width modulation at a time unit shorter than the period of a clock signal within the period of the recording signal. Alternatively, the multivalued input recording signal is converted into a plurality of different signals each of whose length of time is shorter than a clock signal within the period of the recording signal, thereby performing pulse-width modulation in accordance with a predetermined weighting. This makes it possible to obtain a highly toned recording signal without raising the frequency of the clock signal. Further, density tone data is generated in dependence upon inputted multivalued pixel data, and control is performed using both the irradiation time and emission intensity of a light beam based on the generated density tone data. An image is formed by irradiating a photosensitive body with the controlled light beam.
EP96202904A 1989-10-02 1990-10-01 Image forming apparatus and modulating method therein Expired - Lifetime EP0760578B1 (en)

Applications Claiming Priority (10)

Application Number Priority Date Filing Date Title
JP25529489 1989-10-02
JP255294/89 1989-10-02
JP1255294A JP3037345B2 (en) 1989-10-02 1989-10-02 Image data modulation device
JP26822789A JPH03131125A (en) 1989-10-17 1989-10-17 Pulse width modulating circuit
JP268227/89 1989-10-17
JP26822789 1989-10-17
JP1299732A JP2940963B2 (en) 1989-11-20 1989-11-20 Image processing device
JP29973289 1989-11-20
JP299732/89 1989-11-20
EP90310739A EP0421712B1 (en) 1989-10-02 1990-10-01 Image forming apparatus, and modulating method therein

Related Parent Applications (2)

Application Number Title Priority Date Filing Date
EP90310739A Division EP0421712B1 (en) 1989-10-02 1990-10-01 Image forming apparatus, and modulating method therein
EP90310739.9 Division 1990-10-01

Publications (3)

Publication Number Publication Date
EP0760578A2 EP0760578A2 (en) 1997-03-05
EP0760578A3 true EP0760578A3 (en) 1998-03-04
EP0760578B1 EP0760578B1 (en) 2003-04-02

Family

ID=27334417

Family Applications (2)

Application Number Title Priority Date Filing Date
EP90310739A Expired - Lifetime EP0421712B1 (en) 1989-10-02 1990-10-01 Image forming apparatus, and modulating method therein
EP96202904A Expired - Lifetime EP0760578B1 (en) 1989-10-02 1990-10-01 Image forming apparatus and modulating method therein

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP90310739A Expired - Lifetime EP0421712B1 (en) 1989-10-02 1990-10-01 Image forming apparatus, and modulating method therein

Country Status (3)

Country Link
US (2) US5379126A (en)
EP (2) EP0421712B1 (en)
DE (2) DE69030701T2 (en)

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EP0520093B1 (en) * 1991-06-24 1996-09-25 Agfa-Gevaert N.V. Parallel to serial conversion of information data
US5467422A (en) * 1991-08-13 1995-11-14 Konica Corporation Image forming apparatus with neighboring pixel processing
JPH05300346A (en) * 1992-04-20 1993-11-12 Konica Corp Image forming device
DE69520703T2 (en) * 1994-03-02 2001-08-02 Hewlett Packard Co Generation of multi-tone images
GB9407116D0 (en) * 1994-04-11 1994-06-01 Secr Defence Ferroelectric liquid crystal display with greyscale
IT1268925B1 (en) * 1994-04-12 1997-03-13 Syfal Srl EQUIPMENT FOR ENGRAVING CYLINDRICAL RUBBER DIES.
US7031020B1 (en) * 1994-04-22 2006-04-18 Canon Kabushiki Kaisha Image processing method, apparatus and controller
JP3703162B2 (en) * 1994-04-22 2005-10-05 キヤノン株式会社 Image forming apparatus
KR100219831B1 (en) * 1994-12-06 1999-09-01 니시모토 칸이치 Exposure apparatus
JPH08185021A (en) * 1994-12-27 1996-07-16 Canon Inc Image forming device
US5729663A (en) * 1995-12-07 1998-03-17 Xerox Corporation Method and apparatus for gray screening
JP3618912B2 (en) 1996-07-12 2005-02-09 キヤノン株式会社 Image forming apparatus
US6091891A (en) * 1997-05-09 2000-07-18 Lexmark International, Inc. Method and apparatus for calibrating delay lines to create gray levels in continuous tone printing
US5867203A (en) * 1997-05-16 1999-02-02 Lexmark International Inc. EMI reduction in output devices
DE69719317D1 (en) * 1997-07-17 2003-04-03 St Microelectronics Srl System to increase the resolution when converting digital data to PWM signals to control a full-bridge output stage
US6362898B1 (en) * 1997-10-31 2002-03-26 In-System Design, Inc. Pulse width position modulator and clock skew synchronizer
US5990923A (en) * 1997-11-14 1999-11-23 Hewlett-Packard Company High resolution dynamic pulse width modulation
JP3073486B2 (en) * 1998-02-16 2000-08-07 キヤノン株式会社 Image forming apparatus, electron beam apparatus, modulation circuit, and driving method of image forming apparatus
JP3470626B2 (en) * 1999-01-08 2003-11-25 富士ゼロックス株式会社 Electrophotographic apparatus and method
JP3844180B2 (en) * 1999-09-27 2006-11-08 リコープリンティングシステムズ株式会社 Divided distributed PWM gradation processing apparatus and laser printer equipped with the same
JP3983449B2 (en) * 1999-10-15 2007-09-26 株式会社リコー Pulse width modulation circuit, optical writing apparatus, and image forming apparatus
US6476844B1 (en) 2000-10-12 2002-11-05 Lexmark International, Inc. Method and apparatus for electrophotographic laser video modulation and decode for spot fidelity
JP2002356008A (en) * 2001-02-02 2002-12-10 Ricoh Co Ltd Image forming apparatus and method
US6992792B2 (en) * 2001-06-29 2006-01-31 Electronics For Imaging, Inc. Digital pulse width modulator for use in electrostatic printing mechanisms
JP3938144B2 (en) * 2004-02-17 2007-06-27 キヤノン株式会社 Image forming apparatus, control method thereof, and control program
ATE416917T1 (en) * 2004-09-30 2008-12-15 Dainippon Screen Mfg METHOD FOR PRODUCING A PRINTING PLATE AND PRINTING PLATE MAKING APPARATUS
JP2006095931A (en) * 2004-09-30 2006-04-13 Dainippon Screen Mfg Co Ltd Plate making method and plate making apparatus for printing plate
JP4795473B2 (en) * 2009-06-29 2011-10-19 キヤノン株式会社 Image processing apparatus and control method thereof
TWI532323B (en) 2013-08-14 2016-05-01 財團法人工業技術研究院 Digital pulse width generator and generation method thereof
JP2015075748A (en) * 2013-10-11 2015-04-20 キヤノン株式会社 Image forming apparatus, control method of the same, and program
US11513799B2 (en) * 2019-11-04 2022-11-29 Apple Inc. Chained buffers in neural network processor

Citations (20)

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Publication number Priority date Publication date Assignee Title
JPS56138328A (en) * 1980-03-31 1981-10-28 Chiyou Lsi Gijutsu Kenkyu Kumiai Frequency multiplying circuit
US4347523A (en) * 1980-04-24 1982-08-31 Fuji Photo Film Co., Ltd. Laser recorder
US4365202A (en) * 1980-08-25 1982-12-21 Rca Corporation Duty cycle generator with improved resolution
EP0080075A2 (en) * 1981-11-23 1983-06-01 International Business Machines Corporation Method and apparatus for the control of grey level
US4415907A (en) * 1980-11-07 1983-11-15 Hitachi, Ltd. Printing pulse control circuit for thermal printing head
EP0104285A1 (en) * 1982-09-28 1984-04-04 Delta Scan Inc. Method and apparatus for producing images on radiation sensitive recording mediums
JPS59131225A (en) * 1983-01-17 1984-07-28 Fujitsu General Ltd Method and device for modulation of pulse width
JPS59223070A (en) * 1983-06-01 1984-12-14 Canon Inc Laser printer
US4498090A (en) * 1981-02-18 1985-02-05 Sony Corporation Electrostatic printing apparatus
JPS60100831A (en) * 1983-11-07 1985-06-04 Sony Corp Digital/analog converter
JPS60116220A (en) * 1983-11-28 1985-06-22 Matsushita Electric Ind Co Ltd Frequency multiplier for digital signal
JPS6130118A (en) * 1984-07-20 1986-02-12 Nec Corp Timer circuit
US4633222A (en) * 1985-10-01 1986-12-30 Rca Corporation Clock shaping circuit and method
US4679057A (en) * 1984-11-22 1987-07-07 Minolta Camera Kabushiki Kaisha Laser recording apparatus
EP0234809A2 (en) * 1986-02-14 1987-09-02 Canon Kabushiki Kaisha Image processing apparatus
JPS6345973A (en) * 1986-08-12 1988-02-26 Canon Inc Half tone image processing device
GB2196498A (en) * 1986-09-18 1988-04-27 Sony Corp Pulse width modulation control circuit for printing apparatus
US4754291A (en) * 1986-02-24 1988-06-28 Fuji Photo Film Co., Ltd. Light beam scanning recording apparatus width modulation of both total pulse duration and intensity
JPS6467030A (en) * 1987-09-07 1989-03-13 Yamaha Corp Pwm circuit
JPH01129774A (en) * 1987-11-12 1989-05-23 Toshiba Corp Pwm controller

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JPS58114570A (en) * 1981-12-26 1983-07-07 Canon Inc Picture output system
US4800442A (en) * 1985-08-15 1989-01-24 Canon Kabushiki Kaisha Apparatus for generating an image from a digital video signal
JP2647366B2 (en) * 1985-08-29 1997-08-27 キヤノン株式会社 Image processing device
JPH01258953A (en) * 1988-04-08 1989-10-16 Ricoh Co Ltd Laser writing device
US5124802A (en) * 1989-09-26 1992-06-23 Canon Kabushiki Kaisha Electrostatic lasar printer with a short side length of a modulation area formed by pulse width modulation set relative to a detected toner particle size

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56138328A (en) * 1980-03-31 1981-10-28 Chiyou Lsi Gijutsu Kenkyu Kumiai Frequency multiplying circuit
US4347523A (en) * 1980-04-24 1982-08-31 Fuji Photo Film Co., Ltd. Laser recorder
US4365202A (en) * 1980-08-25 1982-12-21 Rca Corporation Duty cycle generator with improved resolution
US4415907A (en) * 1980-11-07 1983-11-15 Hitachi, Ltd. Printing pulse control circuit for thermal printing head
US4498090A (en) * 1981-02-18 1985-02-05 Sony Corporation Electrostatic printing apparatus
EP0080075A2 (en) * 1981-11-23 1983-06-01 International Business Machines Corporation Method and apparatus for the control of grey level
EP0104285A1 (en) * 1982-09-28 1984-04-04 Delta Scan Inc. Method and apparatus for producing images on radiation sensitive recording mediums
JPS59131225A (en) * 1983-01-17 1984-07-28 Fujitsu General Ltd Method and device for modulation of pulse width
JPS59223070A (en) * 1983-06-01 1984-12-14 Canon Inc Laser printer
JPS60100831A (en) * 1983-11-07 1985-06-04 Sony Corp Digital/analog converter
JPS60116220A (en) * 1983-11-28 1985-06-22 Matsushita Electric Ind Co Ltd Frequency multiplier for digital signal
JPS6130118A (en) * 1984-07-20 1986-02-12 Nec Corp Timer circuit
US4679057A (en) * 1984-11-22 1987-07-07 Minolta Camera Kabushiki Kaisha Laser recording apparatus
US4633222A (en) * 1985-10-01 1986-12-30 Rca Corporation Clock shaping circuit and method
EP0234809A2 (en) * 1986-02-14 1987-09-02 Canon Kabushiki Kaisha Image processing apparatus
US4754291A (en) * 1986-02-24 1988-06-28 Fuji Photo Film Co., Ltd. Light beam scanning recording apparatus width modulation of both total pulse duration and intensity
JPS6345973A (en) * 1986-08-12 1988-02-26 Canon Inc Half tone image processing device
GB2196498A (en) * 1986-09-18 1988-04-27 Sony Corp Pulse width modulation control circuit for printing apparatus
JPS6467030A (en) * 1987-09-07 1989-03-13 Yamaha Corp Pwm circuit
JPH01129774A (en) * 1987-11-12 1989-05-23 Toshiba Corp Pwm controller

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PATENT ABSTRACTS OF JAPAN vol. 013, no. 381 (E - 810) 23 August 1989 (1989-08-23) *

Also Published As

Publication number Publication date
US5379126A (en) 1995-01-03
EP0421712A3 (en) 1992-08-19
US5488487A (en) 1996-01-30
EP0760578B1 (en) 2003-04-02
DE69034055D1 (en) 2003-05-08
DE69030701D1 (en) 1997-06-19
EP0421712B1 (en) 1997-05-14
EP0760578A2 (en) 1997-03-05
DE69030701T2 (en) 1997-10-02
EP0421712A2 (en) 1991-04-10

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